The present invention refers to a parallel drive for escalators or moving sidewalks located within the region of reversal and inside the rotating step or parallel belt, with electric motor, gearing, step or pallet drive means and handrail drive means.
In the drives for escalators or moving pavements known up to the present time, in which the drive unit is provided within the region of reversal and inside the rotating passenger conveyor belt, a continuous trend can be noted directed at installing higher powers within this limited space, at reducing the noise of the installation and at providing an economic means of transportation.
Thus modern forms of construction are characterized by a chainless transmission of power from the electric motor in particular to the step or pallet drive shaft, an overhung mounting of the electric motor and its direct flanging to the gear housing leading furthermore to a compact construction (Federal Republic of Germany Pat. No. 25 41 397).
In all previously known designs referred to as head drive, the drive shaft of the electric motor and the input shaft of the gearing are arranged in the direction of movement of the conveyor belt and therefore perpendicular to both the step or pallet drive shaft and the handrail drive shaft. This was done in order to be able to install the necessary electric drive power, and to achieve the necessary reduction in the speed of rotation by means of a worm gearing.
The large step-down ratio and the great quietness in operation possible with of the use of worm gearings undeniably constituted advantages. However, there is still an undiminished need for better economy of such a passenger conveyor belt, directed as a whole at a still smaller structural size of the drive unit with the same or possibly even increased capacity for electric power.
The relatively poor efficiency of the worm gearing and the position of the electric motor in particular provide incentive to look for further solutions.